Applicants claim priority under 35 U.S.C. xc2xa7119 of GERMAN Application No. 100 60 350.5 filed on Dec. 4, 2000. Applicants also claim priority under 35 U.S.C. xc2xa7365 of PCT/DE01/04553 filed on Dec. 1, 2001. The international application under PCT article 21(2) was not published in English.
This invention relates to an aeration and deaeration device for the fuel tank of an internal combustion engine according to the preamble of patent claim 1.
Such a device is known from German Patent 198 13 321 A1.
This invention relates to the problem of determining the composition of the backwashing air more easily and in particular to be able to take this into account with regard to changes during backwashing operation. It should also be possible in engine control to take into account the volume flow and temperature in addition to the composition of the backwashing air.
This problem is solved by an embodiment of a generic device according to the characterizing features of patent claim 1.
Expedient and advantageous embodiments are the object of the subclaims, which also concern methods executable using this device.
This invention is based essentially on the general idea of temporarily passing an air flow in circulation through the packing of the adsorption filter and thereby determine the loading state by means of a sensor mounted in the circulation. Regeneration of the adsorption filter by backwashing may be performed in this way as a function of the loading state determined previously. If, in circulating flow, the loading state detected on the adsorption filter is such that regeneration by backwashing is necessary or desirable, then the same sensor that detected the loading state of the adsorption filter in circulating flow continuously determines the composition of the fluid removed from the circulation line. The fluid leaving the circulation line, i.e., the loaded rinsing air, is sent in particular to the air intake area of the engine. Simultaneously with determination of the composition of the backwashing air, which in principle involves only the hydrocarbon content, the volume flow and temperature of the backwashing air can also be determined. All such state data detected can be used for engine control in supplying purging air into the air intake area of the engine, so that there is no influence on the combustion process that would interfere with the exhaust gas composition during the period when the purging air is being fed into the combustion process. The latter measures, however, are not necessary in this form if the purging air is added directly to the engine exhaust, for example, as is possible in a known manner.
To determine the loading of the adsorption filter with hydrocarbons, it may be sufficient that only a partial area of the filter guide is situated inside the flow circulation which is connected actively for the determination of loading.
The sensor which detects the substance properties and optionally the flow properties and state properties of the purging air may be integrated into an electronic device in which the data detected is processed (further) for forwarding to a central engine control. Sensors that detect the filling level and the pressure inside the tank, namely a pressure sensor and a filling level sensor, may be connected to this electronic device. Therefore, there is an extra electronic device which is separate from the central engine electronics and is connected only to it and may compile all the measurement and control data pertaining to the tank and its aeration and deaeration. This separate electronic device may be part of the adsorption filter, so that an easily handled adsorption filter module is created.
An exemplary embodiment, which is explained in greater detail below, is illustrated in the drawing; in this embodiment, the backwashing air is sent to the air intake area of the internal combustion engine.